A rotary piston pump emerges from German Publication 198 06 657, which comprises two drive shafts for the rotation of the rotors. Both drive shafts are provided at their end in the pump space with screw connections, by means of which the rotors are fixed to the drive shafts. Both drive shafts are produced in one piece and remain in the pump housing during the assembly or dismantling of the rotors. In order that the assembly work is facilitated, one of the drive shafts is connected to the drive by means of a coupling and can thus rotate freely with respect to the other drive shaft in the uncoupled state.
Patent specification U.S. Pat. No. 6,283,740 B3 discloses a rotary piston pump with an improved seal, which is mounted between the rotor and the external diameter of the shaft. An adapter is provided for the drive shaft, with which the drive shaft can easily be coupled to a large number of drive mechanisms. The adapter can be replaced by an alternative adapter in order to match alternative drives.
Patent application US 20080038138 A1 discloses a rotary piston pump with a pump body, with a drive unit and with an external housing, wherein the housing is provided with an insert. The insert comprises a housing made of a plastic material and is provided with an inlet opening and an outlet opening. The housing comprises openings through which the rotors can be driven in a rotary manner, so that the rotors engage in one another and thus pump a fluid from the inlet opening to the outlet opening.